Neuroblastoma in a pair of identical twins.

Hereditary neuroblastoma in a pair of identical twins is reported. In one of the twins the tumor occurred in fetal life and caused death of the twin before birth; in the other one, the tumor occurred at two months of life as IV-S neuroblastoma in the liver with primary tumor undetected. The unusual clinical course of the latter case is described: twice there was tumor regression, but in spite of treatment, fatal uncontrolled growth occurred. The family history, characterized by neoplasms of dissimilar cell types but without additional cases of neuroblastoma, is also detailed.